C/1989 Q1 Okazaki-Levy-Rudenko
more info
Comet C/1989 Q1 was discovered independently by three observers: on 24 August 1989 by Kiyomi Okazaki with a 0.25m-Schmidt camera (Japan), and in the next two days visuallyby David Levy (Arizona) and Michael Rudenko (Massachusetts), that is about 2.5 months before its perihelion passage.This comet was last observed in late December 1989.
Comet had its closest approach to the Earth on 1 December 1989 (0.515 au), less than 3 weeks after perihelion passage.
This is a comet with nongravitational effects strongly manifested in positional data fitting.
Solutions given here are based on data spanning over 0.334 yr in a range of heliocentric distances: 1.63 au – 0.642 au (perihelion) – 1.08 au.
This Oort spike comet suffers tiny planetary perturbations during its passage through the planetary system; these perturbations lead to a little more tight future orbit (see preferred solution).
See also Królikowska 2014 and Królikowska 2020.

solution description
number of observations 231
data interval 1989 08 24 – 1989 12 24
data type significantly more measurements before perihelion (PRE+)
data arc selection entire data set (STD)
range of heliocentric distances 1.63 au – 0.64 au (perihelion) – 1.08 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 452
RMS [arcseconds] 1.30
orbit quality class 2a
orbital elements (heliocentric ecliptic J2000)
Epoch 1989 11 10
perihelion date 1989 11 11.91466426 ± 0.00013837
perihelion distance [au] 0.64236124 ± 0.00000070
eccentricity 1.00002500 ± 0.00001665
argument of perihelion [°] 150.564098 ± 0.000214
ascending node [°] 275.510766 ± 0.000275
inclination [°] 90.146682 ± 0.000248
recip semi-major axis [10-6 au-1] -38.91 ± 25.92
Upper panel: Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line - the moment of perihelion passage.
Lower panel (panels): O-C diagram for this(two) solution (solutions) given in this database, where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
non-gravitational parameters
A1 [10-8au\day-2] 3.3963 ± 0.3166
A2 [10-8au\day-2] 0.50595 ± 0.14936
A3 [10-8au\day-2] 0 (assumed)
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113